7th Asian Biological Inorganic Chemistry Conference Conference Theme: Metalloproteins - Structure and Function
Mo and W SUBSTITUTED RUBREDOXINS
Models for Molybdoenzymes
José J. G. Moura
Email: [email protected]
REQUIMTE/CQFB, Departamento de Química, Faculdade de Ciências e Tecnologia,
Universidade Nova de Lisboa, Campus da Caparica, 2829-516 Caparica, PORTUGAL
The design of metal substituted derivatives in proteins still offers one of the most emerging fields in
the study of metalloproteins. These “novel” compounds can enhance our understanding of the
structural/functional properties and/or design of metalloproteins, whose properties can mimic,
enhance, and/or in some cases improve many features found in the natural ones.[1]
Rubredoxin provides an excellent scaffold for the design of other metal-sulfur substituted
derivatives due to its small size. The iron atom in rubredoxin type proteins is coordinated by four
Cys residues, and can be substituted by a wide range of metals ions by acid precipitation of the
protein (apo-form) and reconstitution in basic media under reducing conditions. Overall, metalsubstituted rubredoxins containing 57Fe(II), Cu(I), Co(II), Ni(II), Zn(II), Cd(II), Hg(II), Ga(III) and
In(III) have been prepared and characterized.[2] The Ni-substituted rubredoxin was speculated as a
size scale intermediate model compound of Ni-site of bacterial hydrogenase.[2] So currently several
metal-substituted derivatives of rubredoxin are available but molybdenum-derivative is absent from
this list. An obvious interest is the possibility of creating a sulfur rich environment, as the one
present in molybdenum enzymes due to the presence of pyranopterins and in some cases additional
coordinating residues, such as cysteine or selenocysteine.[3] Therefore, molybdenum(VI/V/IV) with
cysteine ligands are of interest as model complex for resting or reduced species of active sites of
biologically important molybdenum enzymes. Herein, we report the molybdenum and tungsten
substituted rubredoxin and discuss how far it can be regarded as a model for molybdenum enzymes
(structure and reactivity).
This work was supported by FCT-Portugal (SFRH/BPD/63066/2009, PTDC/QUI-BIQ/098071/2008). Work
in collaboration with Biplab K. Maiti, Cintia Carreira, Luisa B. Maia, Marta S. P. Carepo, Sofia R. Pauleta
and Isabel Moura.
Refs
[1] M. W. Day, T. Hsu, B. L. Joshua-Tor, J.-B. Park, Z. H. Zhou,; M. W. W. Adams, D. C. Rees, Protein Sci. 1992, 1,
1494. [2] P. Saint-Martin, P. A. Lespinat, G. Fauque, Y. Berlier, J. Legall, I. Moura, M. Teixeira, A. V. Xavier, J. J. G.
Moura, Proc Natl Acad Sci U S A 1988, 85, 9378; A.Thapper, A.C. Rizzi, C.D.Brondino, A.G.Wedd, R.J.Pais,
B.K.Maiti, I.Moura, S.R.Pauleta, J.J.G.Moura, J. Inorg. Biochem., 2013, 127, 232-237. [3] R. Hille, Dalton Trans.
42(9), 3029-42 (2013)

Dr .S. Kavita, Project Scientist